Where is the optimal place to have an interface between two different metals?

hey-o!

it is pretty well established scientifically as well as anecdotally that at an interface of two different conductors composed of two different metals, distortion of a signal occurs.  this leads many to choose receptacles and power plugs (as well as IEC inlets and connectors)  made from the same metal.

my question is this: where is the best place to have the interface between different metals in order to reduce distortion?  there obviously needs to be some type of interface since in-wall wiring is copper and internal component wiring is often copper as well. so where does it make the most difference? is it in the receptacle/plug interface where everyone who cares about this focuses their attention? or do they focus their attention here because any of the other interfaces are too much of a pain in the ass to change?  what about the power cable itself?  i see lots of people who like rhodium plated recept/plug combos, but i've never seen any mention of rhodium plated cable.. so there's an interface between two different metals where the connectors join to the cables...

i truly am curious and would love your thoughts and discoveries on the matter.